turn signal

Ok, so something strange has developed recently on the Mustang.

When I signal a right hand turn all is well.

However, when I signal for a left turn....both tail lights flash like I have the hazard lights on or something. Guess I won't be making any left hand turns with a cop behind me in the near future.

I am thinking this is either a bad turn signal switch in the steering column or something not grounded properly? The turn signal switch has been on my short list of things to replace anyway since it seems to be getting worn.

Any thoughts, suggestions or ideas?

Just replaced the rear harness and reverse lights but it is all original style wires.

After looking at it some more today I tried something just grabbing at straws.

I reversed the two wires that plug into the tail light.

My guess is that the reproduction pig tail that plugs into the tail light was wired backwards.

Originally, I had the green with stripe (I think it is) plugged into the matching wire on the pig tail and the black plugged to the black and had the problem of both turn signals going when making a left turn signal.

Today, on a whim just to try...I plugged the black wire into the stripe wire and plugged the stripe wire into the black and everything works fine...

Who knew. Cheap reproductions from China really piss me off sometimes but learning quickly why NOS or original stuff gets so much more money.